This invention relates to a cleaning composition that has an unusually fast evaporation rate. In particular, it relates to a composition of benzotrifluoride and 1,1,2-trichloroethylene.
In manufacturing electronics, textiles, and apparel, it is necessary to remove grease, oil, and other soils left by machinery. A solvent that was widely used in industry for cleaning is 1, 1, 1-trichloroethane because it is non-flammable has a low odor, readily dissolves greases and oils, and has a rapid evaporation rate, which is important for high speed processing. However, 1,1,1-trichloroethane has now been banned because it has found to be an ozone depletor. As a result, there is a great need in the industry for a substitute solvent that has some or all of the desirable properties of 1,1,1-trichloroethane, but which is not an ozone depletor.
We have discovered that a blend of benzotrifluoride (BTF) and 1,1,2-trichloroethylene (TCE) is an excellent substitute solvent for 1,1,1-trichloroethane. This blend is economical, readily dissolves oils and greases, is non-flammable, and has only a slight ethereal odor, which is not regarded as objectionable.
Its most important and unusual property, however, is its high evaporation rate. Not only does this blend dry almost as rapidly as 1,1,1-trichloroethane, but, very unexpectedly, it dries faster than either of its components! That is, the evaporation rate of the blend is higher than the evaporation rate of either benzotrifluoride or 1,1,2-trichloroethylene. As of now we have no explanation for this unusual phenomenon.
The composition of this invention is a blend of about 20 to about 80 wt % benzotrifluoride and about 20 to about 80 wt % TCE. Preferably, the blend is about 60 to 80 wt % benzotrifluoride and about 20 to about 40 wt % TCE because TCE is the more regulated component.
The blend can also include various optional ingredients such as up to about 1 wt % of a stabilizer for the TCE. A stabilizer is preferably present at a concentration of about 0.01 to about 1 wt %. Examples of suitable stabilizers include butylene oxide, ethyl acetate, diisopropyl amine, and epichlorohydrin. The preferred stabilizer is butylene oxide because it stays with the solvent during distillation.
The composition of this invention is a single phase composition and remains a liquid from about xe2x88x9225xc2x0 C. to about 86xc2x0 C. It can be used to clean electronics, textiles, and for contact cleaning and general cleaning. In addition, it can also be used as a solvent carrier for powdered metals, as an ink carrier, or in gravure printing. It can be used as a liquid wash or as an aerosol. Other uses will no doubt be apparent to those skilled in the art.